(1) Field of the Invention
The present invention relates, in general, to agglutination assays. Specifically, the present invention relates to a blood crossmatching apparatus, methods and kits for determining whether mammals are compatible for blood transfusion.
(2) Description of the Related Art
Currently, field veterinarians do not have access to an easy to use, accurate means of evaluating a donor and recipient pair for possible transfusion reactions. Tube agglutination assays are currently used prior to blood transfusion, however these assays are cumbersome and involve erythrocyte preparation and long incubation times. These assays may not always lead to consistent results depending upon the experience of the technician. Additionally, some veterinarians do not have access to a laboratory qualified to perform agglutination assays. Therefore, it would be desirable that a test is available that is quick and simple to use.
Some advancements have been made in the field. U.S. Pat. Nos. 5,338,689, 5,460,940, and 5,863,802 all to Yves et al., and U.S. Pat. Nos. 5,512,432 and 6,114,179 both to Lapierre et al. disclose a method of detecting a target antibody or an antigen on a colored carrier such as an erythrocyte. The method of detection is based upon centrifugation in the presence of inert particles. The inert particles can be cross-linked polymers such as agarose including commercially available particles such as Sepharose® particles. The carrier-bound antigens (ie. erythrocyte antigens) and antibodies have different centrifugation properties than antigen-antibody complexes. If an antigen-antibody complex on a carrier is centrifuged, the carrier-bound complex lies on the inert particles. If no reaction has taken place, the antigen or antibody will pass through the layer of inert particles and come to rest under the particles. Weakly positive reactions may also occur, in which case the carrier-bound antigen-antibody complex is situated within the layer of inert particles.
U.S. Pat. Nos. 5,665,558 and 5,905,028 both to Frame et al. disclose an indirect assay where erythrocytes are exposed to serum antibodies and the mixture is incubated to bind the antibodies to the erythrocytes. In compatibility testing, donor erythrocytes are used in combination with a serum specimen from a patient or donor. If the donor's serum specimen contains IgG antibodies directed against an antigen present on the erythrocytes used in the test, the erythrocytes will adhere to Protein G as a ligand on particles at the top of the matrix. In the case of a weak antigen-antibody reaction, some erythrocytes will adhere to the Protein G agarose particles at the top of the matrix and some will collect at the bottom of the reaction tube. If the serum specimen does not contain antibodies to the antigens present on the erythrocytes, all the erythrocytes will collect at the bottom of the reaction tube. The ligand on the particles can be those known to bind immunoglobulin, such as Protein A, Protein G and Protein A/G.
While the related art teach blood crossmatching kits, there still exists a need for an improved blood crossmatching apparatus that can use whole blood for testing.